1. Field of the Invention
The present invention relates generally to irrigation systems, and more specifically to using orifices of variable diameter to control the amount of water distributed to a discrete area.
2. Description of the Prior Art
Manifolds are described in general as pipes that branch into other pipes and may use diffusers to divide flow. The flow distribution by a diffuser can be through the use of ports, i.e., orifices, cut in the manifold. The hydraulic head along the length of the manifold will decrease due to friction losses, elevational changes and/or momentum changes. The volume of flow from each orifice is also influenced by the magnitude of the flow velocity. Accordingly, the discharge flow from each orifice will be different along the manifold when the orifices are all the same size.
The fluid mechanic principles that are employed to represent a discharge from a manifold orifice are as follows:q=Ka(2gE)0.5 where K=flow coefficient;
a=cross sectional area of port;
E=V2/2 g+Δh; and
V=mean velocity in manifold.
Δh=[(pm/γ)+zm]−[(p0/γ)+zo], and m and o are subscripts that refer to conditions inside and outside the manifold, respectively, at the section where the port is located.
The orifices are spaced at intervals along the manifold and a change in hydraulic head will occur between orifices due to the head losses in the manifold. The head losses can be represented as follows:hf=f(L/D)(V2/2 g)where L=orifice spacing;
D=diameter of manifold; and
V=mean velocity in the manifold.
To obtain a uniform discharge through each orifice, an iterative process is used to calculate the total required head and assumes that the diameter of the manifold, orifice size, and spacing between orifices is uniform. There are many prior art irrigations systems that rely on manifolds with uniformly spaced orifices and diameter of orifices.
For example, U.S. Pat. No. 6,308,902 to Huntley, uses a topographical map to determine the desired spatial relationship of the irrigation conduits. Huntley uses friction losses in the irrigation conduit itself to adjust the volume of water disbursed through each similarly sized and spaced orifice.
However, the shortcomings of Huntley and the prior art include the inability to adapt to variable field conditions and flow requirements without increasing the length of conduit and thereby increasing costs and waste. Accordingly, there is a need in the relevant art for an irrigation system that has the ability to address variable field conditions due to changes in topography or changing flow requirements for a particular type of crop in a more cost effective and efficient manner. All existing irrigation systems of this type that use irrigation conduits with orifices, have the orifices pre-made in the hose before the installation process in the field as described by Huntley.
Another shortcoming of the prior art includes that an inventory of various irrigation conduits with pre-made orifices must be maintained to address variable topography of a field. This increases the overall costs for the irrigation system. Further, prior art irrigation conduits are typically pre-manufactured for a specific location in the field. Therefore, if the designated irrigation conduit is installed at the incorrect location, the irrigation system will not function properly. In addition, the prior art systems use a higher than needed water pressure and waste energy. Accordingly, there is a need in the relevant art for an irrigation system that is efficient and reduces installation error that can lead to the irrigation system not functioning properly.
There is also a need in the art for an improved irrigation system that is installed using specific GPS location coordinates in a field.
Another need exists in the art to provide an improved irrigation system that provides real-time information of existing field conditions.
Another need exists in the art to provide an improved irrigation system that is easy for field workers to operate and to synchronize.
Another need exists in the art to provide an improved irrigation system that is inexpensive to manufacture.
It is, therefore, to the effective resolution of the aforementioned problems and shortcomings of the prior art that the present invention is directed.
However, in view of the prior art at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.